leetcode--Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

For example,
Given [1,3],[2,6],[8,10],[15,18],
return [1,6],[8,10],[15,18].

public class Solution {
    /**There is not special algorithm for this problem.<br>
	 * 1. sort the intervals according to the start point
	 * 2. linear scan the sorted intervals and then merge them together
	 * 
	 * @param intervals --List of Intervals.
	 * @return --List of Intervals, in which no intervals have overlaps 
	 * @author Averill Zheng
	 * @version 2014-06-12--world cup opening day
	 * @since JDK 1.7
	 */
    public List<Interval> merge(List<Interval> intervals) {
        List<Interval> result = new ArrayList<Interval>();
		if(!intervals.isEmpty()){
			Collections.sort(intervals, new IntervalComparator());
			int length = intervals.size();
			int start = intervals.get(0).start;
			int end = intervals.get(0).end;
			for(int i = 1; i < length; ++i){
				Interval current = intervals.get(i);
				if(current.start <= end)
					end = Math.max(end, current.end);
				else{
					result.add(new Interval(start, end));
					start = current.start;
					end = current.end;
				}
			}
			result.add(new Interval(start, end));
		}
		return result;
	}
}

class IntervalComparator implements Comparator<Interval>{
	public int compare(Interval a, Interval b){
		return Integer.compare(a.start, b.start);
	}
}